case.3

linux下qmail的源码 本人加了一些注释

.TH case 3
.SH NAME
case \- convert ASCII uppercase bytes to lowercase
.SH SYNTAX
.B #include <case.h>

void \fBcase_lowers\fP(\fIs\fR);
.br
void \fBcase_lowerb\fP(\fIs\fR,\fIlen\fR);

int \fBcase_diffs\fP(\fIs\fR,\fIt\fR);
.br
int \fBcase_equals\fP(\fIs\fR,\fIt\fR);
.br
int \fBcase_starts\fP(\fIs\fR,\fIt\fR);

int \fBcase_diffb\fP(\fIs\fR,\fIlen\fR,\fIt\fR);
.br
int \fBcase_startb\fP(\fIs\fR,\fIlen\fR,\fIt\fR);

char *\fIs\fR;
.br
char *\fIt\fR;
.br
unsigned int \fIlen\fR;
.SH DESCRIPTION
.B case_lowers
converts each uppercase byte in the string
.I s
to lowercase.
.I s
must be 0-terminated.

.B case_lowerb
converts each uppercase byte in the buffer
.IR s ,
of length
.IR len ,
to lowercase.

.B case_diffs
lexicographically compares lowercase versions of the strings
.I s
and
.IR t .
It returns something positive, negative, or zero
when the first is larger than, smaller than, or equal to the second.
.I s
and
.I t
must be 0-terminated.

.B case_equals
means
.BR !case_diffs .

.B case_starts
returns 1 if a lowercase version of
.I s
starts with a lowercase version of
.IR t .
.I s
and
.I t
must be 0-terminated.

.B case_diffb
lexicographically compares lowercase versions of the buffers
.I s
and
.IR t ,
each of length
.IR len .
It returns something positive, negative, or zero
when the first is larger than, smaller than, or equal to the second.

.B case_startb
returns 1 if a lowercase version of the buffer
.IR s ,
of length
.IR len ,
starts with a lowercase version of the string
.IR t .
.I t
must be 0-terminated.

The
.B case
routines
are ASCII-specific.
They are suitable for programs that handle
case-independent networking protocols.

All comparisons are performed on unsigned bytes.
.SH "SEE ALSO"
byte_diff(3),
byte_equal(3),
str_diff(3),
str_equal(3),
str_start(3)