C Language Functions

Many standard C Runtime functions can be used in Vuser scripts that are in the C language. Expand the categories to locate the desired function.

String Manipulation Functions

Buffer Manipulation Functions

Process Control Functions

Memory Allocation Functions

Mathematics Functions

Input-Output Functions

File Manipulation Functions

Date and Time Functions

Data Type Conversion Functions

Character Classification and Conversion Functions

Alphabetical Listing of C Functions



  • If you try to create a buffer that is too large or if the total size of the local variables is to large, the C interpreter throws an error "Too many local variables" instead of indicating that the buffer is too large. For example, this is an error: char buffer[4096*8];.

    To allocate large buffers, use malloc instead of declaring the buffer as a local variable.

  • In Vugen scripts, you need to explicitly declare C functions that do not return integers. For example, put the following near the beginning of a script that uses the C function strtok:

    extern char* strtok(char *token, const char *delimiter);
  • In Linux C scripting, wchar_t and functions returning a struct or union are not supported for functions from external libraries. For example, div_t div(int a, int b) is not supported.