HP C A.06.05 Reference Manual

C Library Functions
Chapter 8206
{
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f(add1); <This construct is illegal.
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}
Using add1 as an argument causes an error.
The #undef directive may be used to reference a true function instead of a macro.
There are three ways in which a function can be used:
• In a header file (which might generate a macro)
#include <string.h>
i = strlen(x);
• By explicit declaration
extern int strlen();
i=strlen(x);
• By implicit declaration
i = strlen(x);
NOTE It is recommended you always include a header to declare C library functions.
For more information on C library functions, see the HP-UX Reference and HP-UX Linker and
Libraries User Guide.