Ansys Fluent provides some utilities in addition to the standard C I/O functions that you can use to perform input/output (I/O) tasks. These are listed below and are described in the following sections:
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prints a message to the console |
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prints an error message to the console |
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prints a header line at the top of a sample file when using the
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prints one line of particle information to a sample file when using the
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For more information, see the following sections:
The Message function is a utility that displays data to the
console in a format that you specify.
int Message(const char *format,...);
The first argument in the Message function is the format
string. It specifies how the remaining arguments are to be displayed in the console. The
format string is defined within quotes. The value of the replacement variables that follow
the format string will be substituted in the display for all instances of
%type. The % character is used to
designate the character type. Some common format characters are: %d
for integers, %f for floating point numbers,
%g for double data type, and %e for
floating point numbers in exponential format (with e before the
exponent). Consult a C programming language manual for more details. The format string for
Message is similar to printf, the
standard C I/O function (see Standard I/O Functions for details).
In the example below, the text Volume integral of turbulent
dissipation: will be displayed in the console, and the value of the
replacement variable, sum_diss, will be substituted in the message
for all instances of %g.
Example:
Message("Volume integral of turbulent dissipation: %g\n", sum_diss);
/* g represents floating point number in f or e format */
/* \n denotes a new line */
Important: It is recommended that you use Message instead of
printf in compiled UDFs.
You can use Error when you want to stop execution of a UDF and
print an error message to the console.
Example:
if (table_file == NULL)
Error("error reading file");
Important:
Error is not supported by the interpreter and can be used only in
compiled UDFs.
When using DEFINE_DPM_OUTPUT to write a DPM sample file, the
special text output functions par_fprintf and
par_fprintf_head must be used in place of the C I/O function
fprintf. Typically, one or more header lines is written to the
top of the file with column headings or other non-repeating information using
par_fprintf_head. Following the header, a line is written for
each particle sample using par_fprintf. Further details and
examples are provided in the following sections:
The par_fprintf_head function generates a header at the top
of the DPM sample file.
int par_fprintf_head(FILE *fp, const char *format, ...);
The first argument is the file pointer provided by the calling routine defined with
DEFINE_DPM_OUTPUT. The second argument is the format string,
used as described for the Message function in Message
. An example of the usage of
par_fprintf_head is given below:
Example:
par_fprintf_head(fp, "x-coordinate y-coordinate z-coordinate\n");
This prints the column names x-coordinate,
y-coordinate, and z-coordinate
followed by a line feed at the top of the file indicated by FILE
pointer fp. Multiple calls can be made to
par_fprintf_head as needed to write all desired information to
the top of the sample file.
For an illustration of the use of par_fprintf_head within a
DEFINE_DPM_OUTPUT UDF refer to the Example provided in
DEFINE_DPM_OUTPUT
.
The par_fprintf function writes a single particle sample line
into a DPM sample file.
int par_fprintf(FILE *fp, const char *format, ...);
The first argument is the file pointer provided by the calling routine defined with
DEFINE_DPM_OUTPUT. The second argument is the format string,
used as described for the Message function in Message
. When used with
par_fprintf, the first two replacement variables in the format
string must be the particle injection ID and particle ID, respectively. The rest of the
format string can be chosen to specify the output that will be written and its
formatting.
For an illustration of the use of par_fprintf within a
DEFINE_DPM_OUTPUT UDF refer to Example 1 - Sampling and Removing Particles in
DEFINE_DPM_OUTPUT
.