Provided by: libcurl4-doc_8.5.0-2ubuntu10.5_all 
NAME
curl_maprintf, curl_mfprintf, curl_mprintf, curl_msnprintf, curl_msprintf curl_mvaprintf,
curl_mvfprintf, curl_mvprintf, curl_mvsnprintf, curl_mvsprintf - formatted output
conversion
SYNOPSIS
#include <curl/mprintf.h>
int curl_mprintf(const char *format, ...);
int curl_mfprintf(FILE *fd, const char *format, ...);
int curl_msprintf(char *buffer, const char *format, ...);
int curl_msnprintf(char *buffer, size_t maxlength, const char *format, ...);
int curl_mvprintf(const char *format, va_list args);
int curl_mvfprintf(FILE *fd, const char *format, va_list args);
int curl_mvsprintf(char *buffer, const char *format, va_list args);
int curl_mvsnprintf(char *buffer, size_t maxlength, const char *format,
va_list args);
char *curl_maprintf(const char *format , ...);
char *curl_mvaprintf(const char *format, va_list args);
DESCRIPTION
These functions produce output according to the format string and given arguments. They
are mostly clones of the well-known C-style functions but there are slight differences in
behavior.
We discourage users from using any of these functions in new applications.
Functions in the curl_mprintf() family produce output according to a format as described
below. The functions curl_mprintf() and curl_mvprintf() write output to stdout, the
standard output stream; curl_mfprintf() and curl_mvfprintf() write output to the given
output stream; curl_msprintf(), curl_msnprintf(), curl_mvsprintf(), and curl_mvsnprintf()
write to the character string buffer.
The functions curl_msnprintf() and curl_mvsnprintf() write at most maxlength bytes
(including the terminating null byte ('\0')) to buffer.
The functions curl_mvprintf(), curl_mvfprintf(), curl_mvsprintf(), curl_mvsnprintf() are
equivalent to the functions curl_mprintf(), curl_mfprintf(), curl_msprintf(),
curl_msnprintf(), respectively, except that they are called with a va_list instead of a
variable number of arguments. These functions do not call the va_end macro. Because they
invoke the va_arg macro, the value of ap is undefined after the call.
The functions curl_maprintf() and curl_mvaprintf() return the output string as pointer to
a newly allocated memory area. The returned string must be curl_free(3)ed by the receiver.
All of these functions write the output under the control of a format string that
specifies how subsequent arguments are converted for output.
FORMAT STRING
The format string is composed of zero or more directives: ordinary characters (not %),
which are copied unchanged to the output stream; and conversion specifications, each of
which results in fetching zero or more subsequent arguments. Each conversion specification
is introduced by the character %, and ends with a conversion specifier. In between there
may be (in this order) zero or more flags, an optional minimum field width, an optional
precision and an optional length modifier.
The $ modifier
The arguments must correspond properly with the conversion specifier. By default, the
arguments are used in the order given, where each '*' (see Field width and Precision
below) and each conversion specifier asks for the next argument (and it is an error if
insufficiently many arguments are given). One can also specify explicitly which argument
is taken, at each place where an argument is required, by writing "%m$" instead of '%' and
"*m$" instead of '*', where the decimal integer m denotes the position in the argument
list of the desired argument, indexed starting from 1. Thus,
curl_mprintf("%*d", width, num);
and
curl_mprintf("%2$*1$d", width, num);
are equivalent. The second style allows repeated references to the same argument.
If the style using '$' is used, it must be used throughout for all conversions taking an
argument and all width and precision arguments, but it may be mixed with "%%" formats,
which do not consume an argument. There may be no gaps in the numbers of arguments
specified using '$'; for example, if arguments 1 and 3 are specified, argument 2 must also
be specified somewhere in the format string.
Flag characters
The character % is followed by zero or more of the following flags:
# The value should be converted to its "alternate form".
0 The value should be zero padded.
- The converted value is to be left adjusted on the field boundary. (The default is
right justification.) The converted value is padded on the right with blanks,
rather than on the left with blanks or zeros. A '-' overrides a '0' if both are
given.
' ' (a space) A blank should be left before a positive number (or empty string)
produced by a signed conversion.
+ A sign (+ or -) should always be placed before a number produced by a signed
conversion. By default, a sign is used only for negative numbers. A '+' overrides a
space if both are used.
Field width
An optional decimal digit string (with nonzero first digit) specifying a minimum field
width. If the converted value has fewer characters than the field width, it gets padded
with spaces on the left (or right, if the left-adjustment flag has been given). Instead of
a decimal digit string one may write "*" or "*m$" (for some decimal integer m) to specify
that the field width is given in the next argument, or in the m-th argument, respectively,
which must be of type int. A negative field width is taken as a '-' flag followed by a
positive field width. In no case does a nonexistent or small field width cause truncation
of a field; if the result of a conversion is wider than the field width, the field is
expanded to contain the conversion result.
Precision
An optional precision in the form of a period ('.') followed by an optional decimal digit
string. Instead of a decimal digit string one may write "*" or "*m$" (for some decimal
integer m) to specify that the precision is given in the next argument, or in the m-th
argument, respectively, which must be of type int. If the precision is given as just '.',
the precision is taken to be zero. A negative precision is taken as if the precision were
omitted. This gives the minimum number of digits to appear for d, i, o, u, x, and X
conversions, the number of digits to appear after the radix character for a, A, e, E, f,
and F conversions, the maximum number of significant digits for g and G conversions, or
the maximum number of characters to be printed from a string for s and S conversions.
Length modifier
h A following integer conversion corresponds to a short or unsigned short argument.
l (ell) A following integer conversion corresponds to a long or unsigned long
argument, or a following n conversion corresponds to a pointer to a long argument
ll (ell-ell). A following integer conversion corresponds to a long long or unsigned
long long argument, or a following n conversion corresponds to a pointer to a long
long argument.
q A synonym for ll.
L A following a, A, e, E, f, F, g, or G conversion corresponds to a long double
argument.
z A following integer conversion corresponds to a size_t or ssize_t argument.
Conversion specifiers
A character that specifies the type of conversion to be applied. The conversion specifiers
and their meanings are:
d, i The int argument is converted to signed decimal notation. The precision, if any,
gives the minimum number of digits that must appear; if the converted value
requires fewer digits, it is padded on the left with zeros. The default precision
is 1. When 0 is printed with an explicit precision 0, the output is empty.
o, u, x, X
The unsigned int argument is converted to unsigned octal (o), unsigned decimal (u),
or unsigned hexadecimal (x and X) notation. The letters abcdef are used for x
conversions; the letters ABCDEF are used for X conversions. The precision, if any,
gives the minimum number of digits that must appear; if the converted value
requires fewer digits, it is padded on the left with zeros. The default precision
is 1. When 0 is printed with an explicit precision 0, the output is empty.
e, E The double argument is rounded and output in the style "[-]d.ddde±dd"
f, F The double argument is rounded and output to decimal notation in the style
"[-]ddd.ddd".
g, G The double argument is converted in style f or e.
c The int argument is converted to an unsigned char, and the resulting character is
written.
s The const char * argument is expected to be a pointer to an array of character type
(pointer to a string). Characters from the array are written up to (but not
including) a terminating null byte. If a precision is specified, no more than the
number specified are written. If a precision is given, no null byte need be
present; if the precision is not specified, or is greater than the size of the
array, the array must contain a terminating null byte.
p The void * pointer argument is printed in hexadecimal.
n The number of characters written so far is stored into the integer pointed to by
the corresponding argument.
% A '%' is written. No argument is converted.
EXAMPLE
const char *name = "John";
int main(void)
{
curl_mprintf("My name is %s\n", name);
curl_mprintf("Pi is almost %f\n", (double)25.0/8);
}
AVAILABILITY
These functions might be removed from the public libcurl API in the future. Do not use
them in new programs or projects.
RETURN VALUE
The curl_maprintf and curl_mvaprintf functions return a pointer to a newly allocated
string, or NULL if it failed.
All other functions return the number of characters actually printed (excluding the null
byte used to end output to strings). Note that this sometimes differ from how the POSIX
versions of these functions work.
SEE ALSO
printf(3), sprintf(3), fprintf(3), vprintf(3)