dtrace_program_strcompile() Function

After the program has a DTrace handle, the next step is to compile the D program. The consumer uses the dtrace_program_strcompile() function to compile the string that contains the D program. You can also use the dtrace_program_fcompile() function to compile a file that contains a D program. Both of these functions return a pointer to a data structure that describes the compiled program.

dtrace_prog_t *dtrace_program_strcompile(dtrace_hdl_t *dtp, const char *s, dtrace_probespec_t spec, uint_t cflags, int argc, char *const argv[])

The arguments to the dtrace_program_strcompile() function are:

• The DTrace handle.

• A string containing the D program. The dtrace_program_fcompile() function passes a file handle.

• A dtrace_probespec_t spec to indicate the context of the probe you are using, which can be a provider, a module, a function, or a name. For example, if you specify the DTRACE_PROBESPEC_PROVIDER probe, you can specify only provider names. The typical consumer uses only the DTRACE_PROBESPEC_NAME probe.

• Flags. The full list of flags can be found in the /usr/include/dtrace.h file. Some of the common options are:

  DTRACE_C_DIFV

  Shows the target language instructions that results from the compilation and additional information to execute the target language instructions.

  DTRACE_C_ZDEFS

  Instructs the compiler to permit probes, whose definitions do not match the existing probes. By default, the compiler does not allow probe definitions that do not match existing probes.

  DTRACE_C_CPP

  Instructs the compiler to preprocess the input program with the C preprocessor. For more information, see the cpp(1) man page.

• Number of arguments, which are passed to the program.

• Arguments passed to the program.

The arguments to the dtrace_program_fcompile() function are fewer because the dtrace_probespec_t argument is not passed. You can modify the consumer to accept a file specified in the command line by replacing the dtrace_program_strcompile() function with code similar to the following example:

if ((fp = fopen(argv[1], "r")) == NULL)
        fatal("failed to open %s", argv[1]);

if ((prog = dtrace_program_fcompile(g_dtp, fp, 0, 0, NULL)) == NULL) 
        fatal("invalid program");