gen/getobjformat.3

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  27 .Dd September 7, 1998
  28 .Dt GETOBJFORMAT 3
  29 .Os
  30 .Sh NAME
  31 .Nm getobjformat
  32 .Nd get preferred object file format
  33 .Sh LIBRARY
  34 .Lb libc
  35 .Sh SYNOPSIS
  36 .In objformat.h
  37 .Ft int
  38 .Fn getobjformat "char *buf" "size_t bufsize" "int *argcp" "char **argv"
  39 .Sh DESCRIPTION
  40 .Fn getobjformat
  41 queries several sources to determine the preferred object file
  42 format, and copies its name into a buffer provided by the caller.
  43 .Pp
  44 The object file format is determined as follows.  If
  45 .Va argv
  46 is
  47 .No non- Ns Ev NULL
  48 and an explicit command line argument such as
  49 .Fl aout
  50 or
  51 .Fl elf
  52 is present, then that determines the object file format.
  53 .Pp
  54 Otherwise, if the variable
  55 .Ev OBJFORMAT
  56 is set in the environment, the object file format is taken from its
  57 value.
  58 .Pp
  59 Otherwise, if the file
  60 .Pa /etc/objformat
  61 is readable and contains a line of the form
  62 .Ql OBJFORMAT=xxx ,
  63 the object file format is taken from there.
  64 .Pp
  65 Otherwise, a built-in system default object file format is returned.
  66 .Pp
  67 .Va buf
  68 points to a user-supplied buffer into which the name of the object
  69 file format is copied.
  70 .Va bufsize
  71 gives the size of the buffer in bytes.  The string placed in
  72 .Va buf
  73 is always null-terminated.  It is an error if the buffer is too
  74 small to hold the null-terminated name.
  75 .Pp
  76 .Va argv
  77 points to a
  78 .Dv NULL Ns -terminated
  79 argument vector to be scanned for object
  80 format options.
  81 .Va argv
  82 may be
  83 .Dv NULL ,
  84 in which case the argument vector is not scanned.
  85 .Pp
  86 If
  87 .Va argcp
  88 is non-NULL, any object format options are deleted from the
  89 argument vector, and the updated argument count is stored into
  90 the integer referenced by
  91 .Va argcp .
  92 If
  93 .Va argcp
  94 is
  95 .Dv NULL ,
  96 the argument vector is left unchanged.
  97 .Sh RETURN VALUES
  98 On success,
  99 .Fn getobjformat
 100 returns the length of the object file format name, not counting the
 101 null terminator.
 102 If the supplied buffer is too small to hold the object file format
 103 and its null terminator,
 104 .Fn getobjformat
 105 returns -1.  In that case, the contents of the buffer and argument
 106 vector supplied by the caller are indeterminate.
 107 .Sh ENVIRONMENT
 108 .Bl -tag -width OBJFORMAT
 109 .It Ev OBJFORMAT
 110 If the environment variable
 111 .Ev OBJFORMAT
 112 is set, it overrides the default object file format.
 113 .Ev OBJFORMAT takes precedence over
 114 .Pa /etc/objformat .
 115 .El
 116 .Sh FILES
 117 .Bl -tag -width /etc/objformat -compact
 118 .It Pa /etc/objformat
 119 If present, specifies the object file format to use.  Syntax is
 120 .Ql OBJFORMAT=xxx .
 121 .El
 122 .Sh SEE ALSO
 123 .Xr objformat 1
 124 .Sh HISTORY
 125 The
 126 .Fn getobjformat
 127 function first appeared in
 128 .Fx 3.0 .