print(2): document n verb and z flag

print(2): document n verb and z flag

[Amavect .]

Heyo,

print(2): document n verb and z flag
libc.h: add varargck pragmas for n flags

The source for the n flag can take the usual int size flags.
/sys/src/libc/fmt/dofmt.c:/_countfmt/:
In order for the compiler to not complain about these flags,
/sys/include/libc.h needs varargck pragmas.

Thanks,
Amavect

---------

diff -r 94226ee6784b sys/include/libc.h
--- a/sys/include/libc.h    Sun Dec 01 17:57:14 2019 +0100
+++ b/sys/include/libc.h    Sun Dec 01 16:10:29 2019 -0600
@@ -223,6 +223,10 @@
 #pragma    varargck    type    "r"    void
 #pragma    varargck    type    "%"    void
 #pragma    varargck    type    "n"    int*
+#pragma    varargck    type    "hn"    short*
+#pragma    varargck    type    "hhn"    char*
+#pragma    varargck    type    "ln"    long*
+#pragma    varargck    type    "lln"    vlong*
 #pragma    varargck    type    "p"    uintptr
 #pragma    varargck    type    "p"    void*
 #pragma    varargck    flag    ','
diff -r 94226ee6784b sys/man/2/print
--- a/sys/man/2/print    Sun Dec 01 17:57:14 2019 +0100
+++ b/sys/man/2/print    Sun Dec 01 16:10:29 2019 -0600
@@ -200,13 +200,15 @@
 .BR l ,
 .BR ll ,
 .BR u ,
+.BR z ,
 .BR + ,
 .BR - ,
 .BR , ,
 and
 .B #
 to mean pad with zeros,
-short, byte, long, vlong, unsigned, always print a sign, left
justified, commas every three digits,
+short, byte, long, vlong, unsigned, intptr/uintptr,
+always print a sign, left justified, commas every three digits,
 and alternate format.
 Also, a space character in the flag
 position is like
@@ -374,6 +376,17 @@
 in hexadecimal.
 .PP
 The
+.B n
+verb takes the number of bytes written so far and copies it to the
+.B int*
+pointer argument. The flags h, hh, l, ll are interpret the argument type as
+.BR short* ,
+.BR byte* ,
+.BR long* ,
+and
+.BR vlong* .
+.PP
+The
 .B r
 verb takes no arguments; it copies the error string returned by a call to
 .IR errstr (2).