Ubuntu Manpage: curl_maprintf, curl_mfprintf, curl_mprintf, curl_msnprintf, curl_msprintf curl

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 '$' is used, it must be used throughout for all conversions taking an
       argument and all width and precision arguments, but it may be  mixed  with  "%%"  formats,
       which  do  not  consume  an  argument.  There may be no gaps in the numbers of argu‐ ments
       specified using '$'; 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 will be 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, respec‐
       tively, 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 notiation 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

         mprintf("My name is %s\n", name);
         mprintf("Pi is almost %f\n", 25/8);

AVAILABILITY

       These functions will 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.