Exception handling

These case-conversion functions do not return a special value if they encounter an error. To detect an error, initialize the ifx_gl_lc_errno() error number to 0 before you call one of these functions and check ifx_gl_lc_errno() immediately after you call it. The following code fragment performs exception handling in the conversion of a wide character to its lowercase equivalent:

/* Initialize the error number */
ifx_gl_lc_errno() = 0;

/* Perform conversion of 'src_wc' to lowercase */
dst_wc = ifx_gl_towlower(src_wc);

/* If the error number has changed, ifx_gl_towlower() has set
 * it to indicate the cause of an error */
if ( ifx_gl_lc_errno() != 0 )
    /* Handle error */
else
    ...