The following table lists available ANSI C Library functions. Clicking a link in this table opens a topic in the LabWindows/CVI Help in a new browser tab.
| Function | Description |
|---|---|
| _getmbcp | Returns the code page currently used by the operating system. |
| _ismbblead | Returns TRUE if its input byte is a valid lead byte in the current code page. |
| _mbsbtype | Determines the type of the byte in the context string at the given offset. |
| _mbscat | Appends a copy of a source string to the end of a target string. |
| _mbschr | Locates the first occurrence of the specified character in a string. |
| _mbscmp | Compares two NUL-terminated strings. |
| _mbscpy | Copies a source string, including the terminating ASCII NUL byte, into a target string. |
| _mbscspn | Locates the first occurrence in a string of any character from the specified character set. |
| _mbsdec | Moves a character pointer to the previous character in a multibyte character string. |
| _mbsicmp | Compares two NUL-terminated strings. |
| _mbsinc | Moves a character pointer in a multibyte character string to the next character. |
| _mbslen | Returns the length of the specified string up to, but not including, the terminating ASCII NUL byte. |
| _mbsnbcat | Appends a specified number of bytes from a source string to the end of a target string. |
| _mbsnbcmp | Compares a specified number of bytes from two NUL-terminated strings. |
| _mbsnbcpy | Copies a specified number of bytes from a source string to a target string. |
| _mbsnbicmp | Compares not more than a specified amount of bytes of two NUL-terminated strings. |
| _mbspbrk | Locates the first occurrence in a string of any character from the specified character set. |
| _mbsrchr | Locates the last occurrence of the specified character in a given string. |
| _mbsspn | Returns the length in bytes of the initial segment of a string that contains only characters from the specified set of characters. |
| _mbsstr | Locates the first occurrence of a sequence of characters, excluding the terminating ASCII NUL byte, in a string. |
| _mbstok | Breaks a string into tokens, which are separated by one or more characters from the specified set of delimiters. |
| _putenv | Adds or replaces an entry in the environment list of the host environment. |
| abs | Computes the absolute value of the specified integer input value. |
| acos | Computes the principal value of the arc cosine of the specified argument. |
| alloca | Allocates space on the stack for an object of specified size. |
| asctime | Takes a date and time stored in a struct tm and converts it into a string. |
| asin | Computes the principal value of the arc sine of the specified argument. |
| atan | Returns the arc tangent of the specified argument. |
| atan2 | Computes the principal value of the arc tangent of (yValue/xValue) using the signs of both arguments to determine the quadrant of the return value. |
| atof | Converts the initial portion of a string to a double representation. |
| atoi | Converts the initial portion of a string to an int representation. |
| atol | Converts the initial portion of a string to a long int representation. |
| atoll | Converts the initial portion of a string to a long long int representation. |
| bsearch | Searches an array of objects for an element that matches a specified key. |
| calloc | Allocates memory space for an array of elements in which an element's size is specified by elementSize and total number of elements is specified by number_ofElements. |
| ceil | Computes the smallest integer value not less than the specified argument by rounding the input value up to the next highest integer. |
| clearerr | Clears the end-of-file and error indicators for the specified stream. |
| clock | Returns the number of system clock cycles that have occurred since the program started executing. |
| close | Flushes the system buffers for the specified file handle and closes the associated file. |
| cos | Computes the cosine of the specified argument. |
| cosh | Computes the hyperbolic cosine of the specified argument. |
| ctime | Converts the current time to a human-readable string. |
| difftime | Computes the difference between two calendar times. |
| div | Divides numerator by denominator. |
| eof | Tests the end-of-file indicator for the specified handle. |
| exp | Computes the exponential function of the specified argument. |
| fabs | Computes the absolute value of a double. |
| fclose | Flushes the specified I/O stream and closes the associated file. |
| fdopen | Obtains a pointer to a buffered I/O stream from a file handle returned by the open or sopen (Windows only) functions. |
| feof | Tests the end-of-file indicator for the specified stream. |
| ferror | Tests the error indicator for the specified stream. |
| fflush | Flushes the I/O buffer of the specified stream. |
| fgetc | Reads the next character from the specified input stream and advances the associated file position indicator. |
| fgetpos | Obtains the current value of the file position indicator for the specified stream. |
| fgets | Reads characters from the specified input stream into a lineBuffer until end-of-file is encountered, a newline character is read, or (number_ofChars - 1) characters are read. |
| floor | Computes the largest integer value not greater than the specified argument by rounding the input value down to the next lowest integer. |
| fmod | Computes the floating-point remainder of the division of two double values and returns the result. |
| fopen | Opens the specified file according to the designated mode. |
| fprintf | Writes output to the specified stream according to format specifiers in formatString. |
| fputc | Writes the specified character to an output stream and advances the file position indicator. |
| fputs | Writes a string (not including a terminating ASCII NUL byte) to the specified output stream. |
| fread | Reads a block of data from the specified input stream then stores it in the specified buffer. |
| free | Causes the space pointed to by memBlockPointer to be deallocated. |
| freopen | Attempts to close the file that is associated with oldStream, opens a file and associates it with the I/O stream that is pointed to by oldStream, and clears error and end-of-file indicators for the I/O stream. |
| frexp | Splits a floating-point value into two parts: the mantissa (a normalized fraction with magnitude in the interval [0.5,1) or zero) and the exponent (an integral power of two). |
| fscanf | Reads input from the specified stream and converts it into a series of values according to the specifications of the formatting string. |
| fseek | Sets the file position indicator for the specified stream. |
| fsetpos | Sets the file position indicator for the specified stream according to the value obtained from an earlier call to fgetpos. |
| ftell | Returns the current value of the file position indicator for the specified stream. |
| fwrite | Writes a block of data to the specified output stream. |
| getc | Reads the next character from the specified input stream and advances the file position indicator. |
| getenv | Searches for the environment string that matches the specified environment name and returns the associated value to the string. |
| gmtime | Takes a calendar time, breaks it into its component parts, and stores the result in a struct tm. |
| isalnum | Tests to see if a character is alphanumeric (a-z, A-Z, 0-9). |
| isalpha | Tests to see if a character is alphabetic (a-z, A-Z). |
| iscntrl | Tests to see if a character is a control character (any character whose value is from 0 to 31). |
| isdigit | Tests to see if a character is a decimal digit (0-9). |
| isgraph | Tests to see if a character is a printable, non-whitespace character. |
| islower | Tests to see if a character is a lowercase alphabetic character (a - z). |
| isprint | Tests to see if a character is among printable characters, including whitespace. |
| ispunct | Tests to see if a character is a punctuation character, which is any printable character that is neither whitespace nor alphanumeric. |
| isspace | Tests to see if a character is one of the standard whitespace characters. |
| isupper | Tests to see if a character is an uppercase alphabetic character (A - Z). |
| isxdigit | Tests to see if a character is a hexadecimal digit (0-9, A - F, a - f). |
| labs | Computes the absolute value of the specified long integer input value. |
| ldexp | Multiplies a floating-point number by an integral power of two. |
| ldiv | Computes the integral quotient and remainder of the division of numerator by denominator. |
| llabs | Computes the absolute value of the specified long long integer input value. |
| lldiv | Computes the integral quotient and remainder of the division of numerator by denominator. |
| localeconv | Queries the current locale for format parameters for numeric quantities. |
| localtime | Takes a calendar time, breaks it into its component parts, adjusts it to the local time zone, and stores the result in a struct tm. |
| log | Computes the natural logarithm of the specified argument. |
| log10 | Computes the base-ten logarithm of the specified argument. |
| longjmp | Restores the environment saved by the most recent calling of setjmp. |
| lseek | Sets the file position indicator for the specified file handle. |
| malloc | Allocates space for an object of specified size. |
| mblen | Determines the number of bytes contained in the specified multibyte character. |
| mbstowcs | Converts a sequence of multibyte characters into their corresponding wide character codes, storing only a specified number of codes. |
| mbtowc | Determines the number of bytes that are contained in the specified multibyte character and the code that corresponds to that multibyte character. |
| memchr | Locates the first occurrence of the specified character in a given memory block. |
| memcmp | Compares two blocks of memory. |
| memcpy | Copies a specified number of bytes from a source buffer to a target buffer. |
| memmove | Copies a specified number of bytes from a source buffer to a target buffer. |
| memset | Copies a specified value into a memory block. |
| mktime | Converts a local date and time represented in a struct tm into a calendar time value. |
| modf | Breaks a double value into its integral and fractional parts, each of which will have the same sign as the argument. |
| open | Opens a file with the specified name according to the operation flags and returns a handle to the opened file. |
| pow | Raises the input value to the designated power and returns the result. |
| putc | Writes the specified character to an output stream at the position of the associated file position indicator. |
| qsort | Sorts an array of elements into ascending order according to a comparison function written by the user. |
| raise | Sends the specified signal to the executing program. |
| rand | Computes a pseudorandom integer in the range 0 to RAND_MAX. |
| read | Reads a block of data from the specified file handle and stores this data in the specified buffer. |
| realloc | Changes the size of a memory block that has been previously allocated while preserving the contents. |
| remove | Causes the specified file or empty directory to be made inaccessible by that name. |
| rename | Causes the file or directory specified by oldFileName to be known by the name given in newFileName. |
| rewind | Sets the file position indicator for the specified stream to the beginning of the file. |
| setbuf | Specifies how to buffer the I/O stream. |
| setjmp | Stores the current calling environment for later use by longjmp. |
| setlocale | Modifies the specified category of the program's locale. |
| setvbuf | Specifies how to buffer the I/O stream. |
| sin | Computes the sine of the specified argument. |
| sinh | Computes the hyperbolic sine of the specified argument. |
| snprintf | Writes output to the specified string according to format specifiers in formatString; a null character is written at the end of the characters written. |
| sopen | Opens a file with the specified name according to the operation and share flags. |
| sprintf | Writes output to the specified string according to format specifiers in formatString; a null character is written at the end of the characters written. |
| sqrt | Computes the nonnegative square root of the specified argument. |
| srand | Uses the argument as a seed for a new sequence of pseudorandom numbers to be returned by subsequent calls to rand. |
| sscanf | Converts input from the specified source string into a series of values according to the specifiers in formatString. |
| strcat | Appends a copy of a source string to the end of a target string, including the terminating ASCII NUL byte. |
| strchr | Locates the first occurrence of the specified character in a string. |
| strcmp | Compares two NUL-terminated strings. |
| strcoll | Compares two NUL-terminated strings, both interpreted as appropriate to the LC_COLLATE category of the current locale. |
| strcpy | Copies a source string including the terminating ASCII NUL byte into a target string. |
| strcspn | Locates the position of the first character in a string that is in a specified set of characters. |
| strerror | Maps the specified error ID number from the errno global variable to an error message string. |
| strftime | Takes a date and time stored in a time struct and generates a NUL-terminated ASCII string that contains the time and date information in a format specified by a format string. |
| stricmp | Compares two NUL-terminated strings, based on the value of the characters interpreted as an unsigned char. |
| strlen | Computes the length of the specified string, up to but not including the terminating null character. |
| strncat | Appends a specified number of characters from a source string to the end of a target string. |
| strncmp | Compares a specified number of characters of two NUL-terminated strings. |
| strncpy | Copies characters from a source string to a target string until it reaches the specified number of characters or an ASCII NUL byte. |
| strnicmp | Compares a specified number of characters of two NUL-terminated strings based upon the value of the characters in the strings interpreted as unsigned chars. |
| strpbrk | Locates the first occurrence in a string of any character in the specified character set. |
| strrchr | Locates the last occurrence of the specified character in a string. |
| strspn | Locates the position of the first character in a string that is not in a specified set of characters. |
| strstr | Locates the first occurrence of a sequence of characters excluding the terminating ASCII NUL byte in a string. |
| strtod | Converts the initial portion of a string to double representation. |
| strtok | Breaks a string into tokens, which are sequences of contiguous characters separated by one or more characters from the specified set of delimiters. |
| strtol | Converts the initial portion of a string to a long int representation with a specified base. |
| strtoll | Converts the initial portion of a string to a long long integer representation with a specified base. |
| strtoul | Converts the initial portion of a string to an unsigned long int representation with a specified base. |
| strtoull | Converts the initial portion of a string to an unsigned long long integer representation with a specified base. |
| strxfrm | Transforms the specified number of characters, including the terminating ASCII NUL byte, from a source string to a target string. |
| system | Starts running a program and waits for it to exit. |
| tan | Computes the tangent of the specified argument. |
| tanh | Computes the hyperbolic tangent of the specified argument. |
| time | Determines the current calendar time (the number of seconds since January 1, 1900 Coordinated Universal Time (UTC)). |
| tmpfile | Creates a temporary binary file that will be automatically deleted when the user closes the file or terminates the program. |
| tmpnam | Generates a string that is a valid filename and that is not the same as the name of an existing file. This function will generate a different string each time it is called, up to TMP_MAX times. |
| tolower | Converts an uppercase letter to a lowercase letter and returns the converted character. |
| toupper | Converts a lowercase letter to an uppercase letter and returns the converted character. |
| ungetc | Will push a single character back into the specified input stream; subsequent reads on that stream will return pushed-back characters in the reverse order of their pushing. |
| vfprintf | Writes output to the specified stream according to format specifiers in formatString. |
| vfscanf | Reads input from the specified stream and converts it into a series of values according to the specifications of the formatting string. |
| vsnprintf | Writes output to the specified string according to format specifiers in formatString. |
| vsprintf | Writes output to the specified string according to format specifiers in formatString. |
| vsscanf | Converts input from the specified source string into a series of values according to the specifiers in formatString. |
| wcslen | Returns the length of the specified string up to, but not including, the terminating ASCII NUL byte. |
| wcstombs | Converts a sequence of wide character codes into a sequence of the corresponding multibyte characters. |
| wctomb | Determines the number of bytes needed to represent the multibyte character corresponding to the specified wide character code. |
| write | A data block stored in the specified buffer is written to the specified file handle. |