add some man pages

buffer/buffer_get.3

@@ -0,0 +1,26 @@
+.TH buffer_get 3
+.SH NAME
+buffer_get \- read binary data from buffer
+.SH SYNTAX
+.B #include <buffer.h>
+
+int \fBbuffer_get\fP(buffer* \fIb\fR,char* \fIx\fR,unsigned int \fIlen\fR);
+.SH DESCRIPTION
+Normally buffer_get copies data to \fIx\fR[0], \fIx\fR[1], ...,
+\fIx\fR[\fIlen\fR-1] from the beginning of a string stored in
+preallocated space; removes these \fIlen\fR bytes from the string; and
+returns \fIlen\fR.
+
+If, however, the string has fewer than \fIlen\fR (but more than 0)
+bytes, buffer_get copies only that many bytes, and returns that number.
+
+If the string is empty, buffer_get first uses a \fBread operation\fR to
+feed data into the string. The \fBread operation\fR may indicate end of
+input, in which case buffer_get returns 0; or a read error, in which
+case buffer_get returns -1, setting \fIerrno\fR approporiately.
+
+The preallocated space and the \fBread operation\fR are specified by
+\fIb\fR. You must initialize \fBb\fR using buffer_init before calling
+buffer_get (or use the pre-initialized buffer_0).
+.SH "SEE ALSO"
+buffer_init(3), buffer_feed(3), buffer_peek(3), buffer_seek(3), buffer(3)