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$ make hello world in Java Get barcode pdf417 in Java $ make hello world




How to generate, print barcode using .NET, Java sdk library control with example project source code free download:
$ make hello world generate, create pdf417 2d barcode none in java projects iReport for Jasper Server 2 Building from Source The term function is a little misleading. make is not a programming language, and it provides only minimal error checking. Just like variables, make is happy to return empty strings when you make mistakes.

Because a function definition looks no different from a variable definition, for example, you can still use a function as a variable. This seems weird, but it is consistent, given the syntax used for functions. When you use a function as a variable, it behaves as though the function were called with no arguments.

For example:. $(call myfunction) # applet PDF-417 2d barcode is the same as...

$(myfunction). In both cases, the po sitional arguments $(1), $(2), and so on are replaced with empty strings. 2.2.

2.9 Conditional Constructs Conditional constructs are another useful GNU extension for controlling make behavior. There are only four types of conditionals supported in GNU make, and these are listed in Table 2-5.

There really are only two tests and their complements: if equal and if defined. Because make does not have a not operator, it is necessary to have separate keywords for equal and not equal, as well as for defined and not defined. Each conditional block may have an optional else clause but must be terminated by an endif.

The basic syntax is as follows:. conditional test make pdf417 for Java file text evaluated when test is true else makefile text evaluated when test is false endif. TABLE 2-5. Conditionals Available in GNU Make Conditional ifeq ifneq ifdef ifndef Usage Test if two val ues are equal Test if two values are not equal Test if a variable is defined Test if a variable is not defined. Build Tools The text that appears inside the conditional clause may be any valid make lines, but conditionals may not be used inside the command section of rules or inside variable/ function definitions. This places some restrictions on how conditionals may be used. Let s start with a simple example using the ifeq conditional:.

ifeq ($(shell uname -o),GNU/Linux) CPPFLAGS += -DLINUX endif Here, we use the ifeq conditional to test for the type of OS. It uses the output of the shell command uname -o to indicate the type of operating system, which is GNU/Linux on my Linux system. So when this appears in a Makefile on a Linux system, the CPPFLAGS variable will include the -DLINUX flag.

Recall that CPPFLAGS is used in implicit rules for targets that are built with tools that use the C preprocessor. This is one technique for using conditionals to support multiple build environments. Adding an else clause is straightforward:.

ifeq ($(shell uname -o),GNU/Linux) CPPFLAGS += -DLINUX else CPPFLAGS += -DOS_UNKNOWN endif You can also wrap con ditional clauses around rules as well, so the following syntax is valid:. ifeq ($(shell uname -o),GNU/Linux) all: linux_programs else all: bsd_programs endif The command portion o f the rule can be inside or outside the conditional clause. One thing worth noting is that conditionals are evaluated in line with variable assignments, as illustrated by this silly example:. ifeq ($(A),0) # A isn"t defined yet all: @echo $(A) == 0 else all: @echo $(A) != 0 endif A=0 2 Building from Source Now when you run this barcode pdf417 for Java Makefile, you see the following illogical output:. $ make 0 != 0. The problem is that t PDF417 for Java he macro A is not defined until after the conditional, so the test fails (it s false). See what I mean about no error checking The ifdef clause tests for variable definitions, which can be useful for using variables as command-line options. For example:.

ifeq ifdef (debug) CFLAGS += -g else CFLAGS += -O2 endif Recall that CFLAGS is the built-in variable used for implicitly building an object from C source code. In this example, the default setting for CFLAGS is to include optimization with the -O2 switch. If you want to compile for debugging, invoke make with debug defined on the command line as follows:.

$ make debug=1 In large, complicated Makefiles, you might use ifdef to make sure that a necessary variable is set:. ifndef (A_VITAL_VARIABLE) $(error A_VITAL_VARIABLE is not set) endif 2.2.2.

10 Pulling Sour ce from Various Places Very often, projects with many source files will locate them in a single directory and build them in a different one. This reduces clutter by keeping one type of file in a directory. Traditionally, this is accomplished with the VPATH variable.

As usual, however, GNU make extends this functionality in many useful ways. In principle, the VPATH variable works much like the shell PATH variable. It contains a list of directories separated by colons, in which it searches for targets and prerequisites.

You might have a project with two directories: src for source files and bin for objects. In this case, the Makefile usually would reside in the ./bin directory and would look something like this:.

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