◄Up► ◄Contents► ◄Index► ◄Back► ─────PWB Extensions───────────────────────────────────────────────────────── You can write many extensions by using only PWB callback functions, but sometimes you may need C functions to work on strings or arrays. Note that PWB defines some string functions. The following categories of C functions can be used within extensions: ■ String manipulation, except strdup (STRING.H) ■ Buffer manipulation (MEMORY.H) ■ Character classification and conversion (CTYPE.H) ■ Data conversion, except strtod (STDLIB.H) Most other functions in the C library are incompatible with extensions. Specifically, the following categories of functions cannot be called in extensions: ■ Functions that depend on C startup code support, including most I/O routines (use PWB file and text callback functions instead). ■ Dynamic memory-allocation functions (malloc, for example) and functions that call them. Use the PWB Falloc and Fdalloc callback functions instead. ■ Process control functions from the exec and spawn families. Use the PWB DoSpawn callback function. If you are not sure whether a function is compatible with PWB extensions, you can always try using the function. You will get linker errors if the library function is not compatible. See: ◄Building Extension Modules► -♦-