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Fix vararg documentation for Python 3

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Memory handling is different to Python 2.
This commit is contained in:
William S Fulton 2013-05-24 22:51:27 +01:00
commit f15eb3f5ec
3 changed files with 40 additions and 22 deletions
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32
Doc/Manual/Varargs.html
View file

@ -509,10 +509,10 @@ like this:
<div class="code">
<pre>
%typemap(in) (...)(char *args[10]) {
%typemap(in) (...)(char *vargs[10]) {
int i;
int argc;
for (i = 0; i &lt; 10; i++) args[i] = 0;
for (i = 0; i &lt; 10; i++) vargs[i] = 0;
argc = PyTuple_Size(varargs);
if (argc &gt; 10) {
PyErr_SetString(PyExc_ValueError, "Too many arguments");
@ -528,7 +528,7 @@ like this:
return NULL;
}
pystr = PyUnicode_AsUTF8String(pyobj);
str = PyBytes_AsString(pystr);
str = strdup(PyBytes_AsString(pystr));
Py_XDECREF(pystr);
%#else
if (!PyString_Check(pyobj)) {
@ -537,22 +537,34 @@ like this:
}
str = PyString_AsString(pyobj);
%#endif
args[i] = str;
vargs[i] = str;
}
$1 = (void *) args;
$1 = (void *)vargs;
}
%typemap(freearg) (...) {
%#if PY_VERSION_HEX&gt;=0x03000000
int i;
for (i = 0; i &lt; 10; i++) {
free(vargs$argnum[i]);
}
%#endif
}
</pre>
</div>
<p>
In this typemap, the special variable <tt>varargs</tt> is a tuple
In the 'in' typemap, the special variable <tt>varargs</tt> is a tuple
holding all of the extra arguments passed (this is specific to the
Python module). The typemap then pulls this apart and sticks the
values into the array of strings <tt>args</tt>. Then, the array is
assigned to <tt>$1</tt> (recall that this is the <tt>void *</tt>
variable corresponding to <tt>(...)</tt>). However, this assignment
is only half of the picture----clearly this alone is not enough to
make the function work. To patch everything up, you have to rewrite the
make the function work. The 'freearg' typemap cleans up memory
allocated in the 'in' typemap; this code is generated to be called
after the <tt>execlp</tt> function is called. To patch everything
up, you have to rewrite the
underlying action code using the <tt>%feature</tt> directive like
this:
</p>
@ -560,9 +572,9 @@ this:
<div class="code">
<pre>
%feature("action") execlp {
char *args = (char **) arg3;
result = execlp(arg1, arg2, args[0], args[1], args[2], args[3], args[4],
args[5],args[6],args[7],args[8],args[9], NULL);
char **vargs = (char **) arg3;
result = execlp(arg1, arg2, vargs[0], vargs[1], vargs[2], vargs[3], vargs[4],
vargs[5], vargs[6], vargs[7], vargs[8], vargs[9], NULL);
}
int execlp(const char *path, const char *arg, ...);

2
Examples/test-suite/python/python_varargs_typemap_runme.py
View file

@ -4,4 +4,4 @@ if (python_varargs_typemap.testfunc(1, 2.0, "three") != "three") :
raise RuntimeError("testfunc failed!")
if (python_varargs_typemap.testfunc(1, 2.0, "three", "four", "five") != "threefourfive") :
raise RuntimeError("testfunc failed!")
raise RuntimeError("testfunc failed! {}")

28
Examples/test-suite/python_varargs_typemap.i
View file

@ -4,13 +4,10 @@
* chapter of the SWIG manual.
*/
%{
%}
%typemap(in) (...)(char *args[10]) {
%typemap(in) (...)(char *vargs[10]) {
int i;
int argc;
for (i = 0; i < 10; i++) args[i] = 0;
for (i = 0; i < 10; i++) vargs[i] = 0;
argc = PyTuple_Size(varargs);
if (argc > 10) {
PyErr_SetString(PyExc_ValueError, "Too many arguments");
@ -26,7 +23,7 @@
return NULL;
}
pystr = PyUnicode_AsUTF8String(pyobj);
str = PyBytes_AsString(pystr);
str = strdup(PyBytes_AsString(pystr));
Py_XDECREF(pystr);
%#else
if (!PyString_Check(pyobj)) {
@ -35,15 +32,24 @@
}
str = PyString_AsString(pyobj);
%#endif
args[i] = str;
vargs[i] = str;
}
$1 = (void *) args;
$1 = (void *)vargs;
}
%feature("action") testfunc {
char **args = (char **) arg3;
result = testfunc(arg1, arg2, args[0], args[1], args[2], args[3], args[4],
args[5],args[6],args[7],args[8],args[9], NULL);
char **vargs = (char **) arg3;
result = testfunc(arg1, arg2, vargs[0], vargs[1], vargs[2], vargs[3], vargs[4],
vargs[5], vargs[6], vargs[7], vargs[8], vargs[9], NULL);
}
%typemap(freearg) (...) {
%#if PY_VERSION_HEX>=0x03000000
int i;
for (i = 0; i < 10; i++) {
free(vargs$argnum[i]);
}
%#endif
}
%inline {