WSTestUCS2Head()
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int WSTestUCS2Head(WSLINK l, const unsigned short *h, int v, int *n)
tests that the next expression to be read from l is an expression with the head h and a UCS2 encoded name of length v, and stores the number of arguments of the expression in n.

DetailsDetails

  • WSTestUCS2Head() fails if the current expression on the link is not a function with a symbol as a head, or if the name of the symbol does not match h.
  • WSTestUCS2Head() returns 0 in the event of an error, and a nonzero value if the function succeeds.
  • Use WSError() to retrieve the error code if WSTestUCS2Head() fails.
  • WSTestUCS2Head() will reset the stream pointer to the expression on the link just prior to calling WSTestUCS2Head() if the function fails. This operation behaves as if the programmer called WSCreateMark(l); WSTestUCS2Head(); WSSeekToMark().
  • WSTestUCS2Head() is declared in the WSTP header file wstp.h.

ExamplesExamplesopen allclose all

Basic Examples  (1)Basic Examples  (1)

#include "wstp.h"

/* A function for testing whether the next expression on the link is a ReturnPacket[] */

void f(WSINK l)
{
    const unsigned short packet[12];
    int arguments;

    packet[0] = 'R';
    packet[1] = 'e';
    packet[2] = 't';
    packet[3] = 'u';
    packet[4] = 'r';
    packet[5] = 'n';
    packet[6] = 'P';
    packet[7] = 'a';
    packet[8] = 'c';
    packet[9] = 'k';
    packet[10] = 'e';
    packet[11] = 't';

    if(! WSTestUCS2Head(l, (const unsigned short *)packet, 12,
        &arguments))
    { /* read the contents of the ReturnPacket[] */ }
    else
    { /* the head of the incoming expression is not ReturnPacket */ }
}
Introduced in 2014
(10.0)