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path: root/Help/guide/tutorial/Step3/tutorial.cxx
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// A simple program that computes the square root of a number
#include <cmath>
#include <iostream>
#include <string>

#include "MathFunctions.h"
#include "TutorialConfig.h"

int main(int argc, char* argv[])
{
  if (argc < 2) {
    // report version
    std::cout << argv[0] << " Version " << Tutorial_VERSION_MAJOR << "."
              << Tutorial_VERSION_MINOR << std::endl;
    std::cout << "Usage: " << argv[0] << " number" << std::endl;
    return 1;
  }

  // convert input to double
  const double inputValue = std::stod(argv[1]);

  const double outputValue = mathfunctions::sqrt(inputValue);

  std::cout << "The square root of " << inputValue << " is " << outputValue
            << std::endl;
  return 0;
}
="hl ppc"> /* ./configure sets HAVE_DYNAMIC_LOADING if dynamic loading of modules is supported on this platform. configure will then compile and link in one of the dynload_*.c files, as appropriate. We will call a function in those modules to get a function pointer to the module's init function. */ #ifdef HAVE_DYNAMIC_LOADING #include "importdl.h" #ifdef MS_WINDOWS extern dl_funcptr _PyImport_GetDynLoadWindows(const char *shortname, PyObject *pathname, FILE *fp); #else extern dl_funcptr _PyImport_GetDynLoadFunc(const char *shortname, const char *pathname, FILE *fp); #endif PyObject * _PyImport_LoadDynamicModule(PyObject *name, PyObject *path, FILE *fp) { PyObject *m = NULL; #ifndef MS_WINDOWS PyObject *pathbytes; #endif PyObject *nameascii; char *namestr, *lastdot, *shortname, *packagecontext, *oldcontext; dl_funcptr p0; PyObject* (*p)(void); struct PyModuleDef *def; m = _PyImport_FindExtensionObject(name, path); if (m != NULL) { Py_INCREF(m); return m; } /* name must be encodable to ASCII because dynamic module must have a function called "PyInit_NAME", they are written in C, and the C language doesn't accept non-ASCII identifiers. */ nameascii = PyUnicode_AsEncodedString(name, "ascii", NULL); if (nameascii == NULL) return NULL; namestr = PyBytes_AS_STRING(nameascii); if (namestr == NULL) goto error; lastdot = strrchr(namestr, '.'); if (lastdot == NULL) { packagecontext = NULL; shortname = namestr; } else { packagecontext = namestr; shortname = lastdot+1; } #ifdef MS_WINDOWS p0 = _PyImport_GetDynLoadWindows(shortname, path, fp); #else pathbytes = PyUnicode_EncodeFSDefault(path); if (pathbytes == NULL) goto error; p0 = _PyImport_GetDynLoadFunc(shortname, PyBytes_AS_STRING(pathbytes), fp); Py_DECREF(pathbytes); #endif p = (PyObject*(*)(void))p0; if (PyErr_Occurred()) goto error; if (p == NULL) { PyObject *msg = PyUnicode_FromFormat("dynamic module does not define " "init function (PyInit_%s)", shortname); if (msg == NULL) goto error; PyErr_SetImportError(msg, name, path); Py_DECREF(msg); goto error; } oldcontext = _Py_PackageContext; _Py_PackageContext = packagecontext; m = (*p)(); _Py_PackageContext = oldcontext; if (m == NULL) goto error; if (PyErr_Occurred()) { PyErr_Format(PyExc_SystemError, "initialization of %s raised unreported exception", shortname); goto error; } /* Remember pointer to module init function. */ def = PyModule_GetDef(m); if (def == NULL) { PyErr_Format(PyExc_SystemError, "initialization of %s did not return an extension " "module", shortname); goto error; } def->m_base.m_init = p; /* Remember the filename as the __file__ attribute */ if (PyModule_AddObject(m, "__file__", path) < 0) PyErr_Clear(); /* Not important enough to report */ else Py_INCREF(path); if (_PyImport_FixupExtensionObject(m, name, path) < 0) goto error; Py_DECREF(nameascii); return m; error: Py_DECREF(nameascii); Py_XDECREF(m); return NULL; } #endif /* HAVE_DYNAMIC_LOADING */