ERRSTR(2) System Calls Manual ERRSTR(2)
NAME
errstr, werrstr - description of last system call error
SYNOPSIS
#include <u.h>
#include <libc.h>
int errstr(char *err)
void werrstr(char *fmt, ...)
DESCRIPTION
When a system call fails it returns -1 and records a string describing the error in a per-process buffer. Errstr swaps the contents of
that buffer with the contents of the array err. Err should contain at least ERRLEN characters (defined in <libc.h>). Usually errstr will
be called with an empty string, but the exchange property provides a mechanism for libraries to set the return value for the next call to
errstr.
If no system call has generated an error since the last call to errstr with an empty string, the result is an empty string.
The verb r in print(2) calls errstr and outputs the error string.
Werrstr takes a print style format as its argument and uses it to format a string to pass to errstr. The string returned from errstr is
discarded.
SOURCE
/sys/src/libc/9syscall
/sys/src/libc/9sys/werrstr.c
DIAGNOSTICS
Errstr always returns 0.
SEE ALSO
intro(2), perror(2)
ERRSTR(2)
