FPC Version Switcher: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		## About
2	2
3	3		The FPC version switcher package integrates with the Lazarus IDE in order to allow easy switching of fpc versions.
4	4
5		-	~~<figure>~~
6		-	~~<img src="fpcversion.jpg" title="fpcversion.jpg" />~~
7		-	~~<figcaption>fpcversion.jpg</figcaption>~~
8		-	~~</figure>~~
	5	+	![](/wiki-images/0/05/Fpcversion.jpg)
9	6
10	7		## Background
11	8
12	9		### Actual compiler naming convention
13	10
14	11		The actual FPC compiler / cross-compiler is usually ppcxxx or ppcrossxxx where xxx denotes the cpu target.
15	12
16	13		For an i386 (32 bit) system:
17	14
18	15		- ppc386 is the actual compiler
19	16		- ppcrossx64 is the actual x86_64 cross compiler (produces 64 bit binaries)
20	17		- ppcrossarm is the actual arm cross compiler (produces arm binaries)
21	18
22	19		etc...
23	20
24	21		For an x86_64 (64 bit) system:
25	22
26	23		- ppcx64 is the actual compiler
27	24		- ppcross386 is the actual i386 cross compiler (produces 32 bit binaries)
28	25		- ppcrossarm is the actual arm cross compiler (produces arm binaries)
29	26
30	27		etc...
31	28
32	29		### The fpc frontend executable
33	30
34	31		Rather than letting one guess the actual compiler name for a certain target cpu and call it directly, FPC provides the fpc front end executable, which takes care of calling the right actual compiler for the required target cpu. To do that, 3 things are needed:
35	32
36	33		- The OS should be able to locate the fpc executable by either:
37	34		- adding the fpc executable path to the environment PATH variable (eg export PATH=/usr/bin;\$PATH) and just calling "fpc".
38	35		- providing a fully qualified path (eg /usr/bin/fpc).
39	36
40	37		- The fpc executable should be told what the target cpu is by using the -P\<target_cpu\> switch so that it can deduce by itself the actual compiler name.
41	38
42	39		- The fpc executable should be able to locate the actual compiler by either:
43	40		- adding the actual compiler (ppcxxx) path to the environment PATH variable (eg export PATH=/usr/lib/fpc;\$PATH)
44	41		- calling fpc with the -Xp\<ppcxxx_path\> switch to inform it about the location of the actual compiler (eg: fpc -Xp/usr/lib/fpc)
45	42
46	43		Some users opt to create in one folder symlinks with the fpc version suffixed (eg ppc386-3.1.1), and pointing to the actual compilers. The -V\<version\> switch lets the fpc executable append \<version\> to the actual compiler name (eg fpc -V3.1.1 on a 386 system will look for ppc386-3.1.1).
47	44
48	45		To sum up, calling fpc can take different forms:
49	46
50	47		- fpc -P\<cpu_target\>
51	48		- /usr/bin/fpc -Xp/usr/lib/fpc -P\<cpu_target\>
52	49		- /usr/bin/fpc -Xp/usr/lib/fpc -V3.1.1 -P\<cpu_target\>
53	50
54	51		etc...
55	52
56	53		### Checking fpc's mechanism
57	54
58	55		#### Processor name
59	56
60	57		The -PP switch just displays the processor name.
61	58
62	59		- On an i386 system (32 bit), the output of fpc -PP is i386
63	60		- On an x86_64 system (64 bit), the output of fpc -PP is x86_64
64	61
65	62		#### Actual compiler name name
66	63
67	64		The -PB switch will make fpc just display the actual compiler name for a target cpu.
68	65
69	66		On an i386 system (32 bit):
70	67
71	68		- fpc -PB will output ppc386 (default cpu target)
72	69		- fpc -Pi386 -PB will output ppc386
73	70		- fpc -Px86_64 -PB will output ppcrossx64
74	71		- fpc -Parm -PB will output ppcrossarm
75	72
76	73		etc...
77	74
78	75		On an x86_64 system (64 bit):
79	76
80	77		- fpc -PB will output ppcx64 (default cpu target)
81	78		- fpc -Px86_64 -PB will output ppcx64
82	79		- fpc -Pi386 -PB will output ppcross386
83	80		- fpc -Parm -PB will output ppcrossarm
84	81
85	82		etc...
86	83
87	84		One can even use it as follows:
88	85
89	86		\<path_to_fpc_bin\>/fpc -Xp\<\<path_to_fpc_lib\> -V\<fpc_version\> -P\<cpu_target\> -PB
90	87
91	88		### Compiler utilities
92	89
93	90		The actual compiler, once called, may need to locate some utilities. The path can be specified by either:
94	91
95	92		- Adding the compiler utilities path to the environment PATH variable (eg export PATH=/usr/local/bin/compiler_utilities;\$PATH)
96	93		- Adding the -FD\<compiler_utilities_path\> switch to fpc.cfg (eg: -FD/usr/local/bin/compiler_utilities)
97	94		- Calling fpc with the -FD\<compiler_utilities_path\> switch (eg: fpc -FD/usr/local/bin/compiler_utilities)
98	95
99	96		### Cross binutils
100	97
101	98		For cross compiling, the cross binutils (cross assembler, cross linker, ...) folder should be in the environment PATH variable.
102	99
103	100		## FPC Version Switcher
104	101
105	102		The FPC version switcher package allows tweaking all the above options and even providing a dropdown list in the IDE Tools/Options/Compiler Version in order to select the required fpc version, and set the \$(UseFPCVersion) macro accordingly.
106	103
107	104		Now, if the installations of the different fpc versions differ only by the version number (eg /usr/lib/fpc/2.6.4 and /usr/lib/fpc/3.1.1), then one can specify paths based on that macro (eg /usr/lib/fpc/\$(UseFPCVersion)). Moreover, any IDE macro other than \$(FPCVER) and that doesn't depend on it can be used in the paths (eg \$Env(HOME)/fpc/lib/\$(UseFPCVersion)).
108	105
109	106		### Pre-requisites
110	107
111	108		1. Having multiple fpc versions installed
112	109		2. Having a homogeneous directory structure (paths for different fpc versions should differ only by version number)
113	110		3. Modifying all paths in fpc.cfg to depend on FPC's \$FPCVERSION macro (where applicable)
114	111		4. Not having fpc related paths in the environment PATH variable (except as outlined in #Setting the fpc frontend executable path)
115	112		5. Having "fpc" as compiler executable in the IDE's Tools/Options/Files
116	113
117	114		### Installation
118	115
119	116		Open fpcversionswitcher.lpk in the lazarus/components/fpcversionswitcher folder, compile and install it and restart the IDE. A new frame will be available in Tools/Options/Compiler Version.
120	117
121	118		### FPC version selection
122	119
123	120		Enter or select the required FPC version using the dropdown list. This will set the \$(UseFPCVersion) macro accordingly. Note that this macro is different from the IDE's \$(FPCVER) macro.
124	121
125	122		### Setting the fpc frontend executable path
126	123
127	124		Enter or locate the absolute path of the fpc frontend executable. You can use \$(UseFPCVersion) and/or any IDE macro other than and doesn't depend on \$(FPCVER).
128	125
129	126		Select how the IDE should locate the fpc frontend:
130	127
131	128		- By adding the path to the environment PATH variable
132	129		- By calling the fpc executable with a fully qualified path
133	130		- By doing nothing and assuming that the path has been predefined in the environment PATH variable
134	131
135	132		### Setting the actual compiler executable path
136	133
137	134		Enter or locate the absolute path of the actual compiler executable. You can use \$(UseFPCVersion) and/or any IDE macro other than and doesn't depend on \$(FPCVER).
138	135
139	136		Select how the IDE should locate the actual compiler:
140	137
141	138		- By adding the path to the environment PATH variable
142	139		- By calling the fpc executable with the Xp switch and a fully qualified path
143	140
144	141		### Setting the compiler utilities path
145	142
146	143		Enter or locate the absolute path of the compiler utilities. You can use \$(UseFPCVersion) and any IDE macro other than and/or doesn't depend on \$(FPCVER).
147	144
148	145		Select how the IDE should locate the actual compiler:
149	146
150	147		- By adding the path to the environment PATH variable
151	148		- By calling the fpc executable with the FD switch and a fully qualified path
152	149		- By doing nothing and assuming that the FD switch is used in fpc.cfg
153	150
154	151		### Enabling the version suffix for the actual compiler
155	152
156	153		Check "ppc executable has suffix" if the actual compilers or symlinks pointing to them have the fpc version suffixed (eg ppc386-3.1.1)
157	154
158	155		### Mechanism
159	156
160	157		- FPC Version Switcher modifies the environment PATH variable for settings that require it to do so
161	158		- FPC Version Switcher passes to the IDE a prefix (the fpc frontend path or empty) which the IDE should prepend to "fpc"
162	159		- FPC Version Switcher passes to the IDE a suffix (the -Xp, -FD, and -V switches if any) which the IDE should append to "fpc"
163	160
164	161		### Verifying the settings
165	162
166	163		The check button will display:
167	164
168	165		- If the fpc frontend path should exist in the environment PATH variable before launching the IDE
169	166		- Which paths will be added to the environment PATH variable
170	167		- How the IDE should call the fpc frontend
171	168
172	169		### Usage
173	170
174	171		To change the fpc version, it is enough to go to Tools/Options/Compiler version and select the required FPC version. You can then compile your projects or the IDE with that version.
175	172
176	173		### Use cases with different fpc and ppc folders setups
177	174
178	175		For the sake of brevity, the fpc frontend executable folder and the actual compiler folder will be denoted as the bin and lib folders respectively,
179	176
180	177		#### Common bin folder and separate lib folders
181	178
182	179		- fpc executable path: /usr/local/bin
183	180		- ppcxxx executable path: /usr/local/lib/fpc/\$(UseFPCVersion)
184	181
185	182		#### Separate bin folders and separate lib folders
186	183
187	184		- fpc executable path: \$Env(HOME)/fpc/\$(UseFPCVersion)/bin
188	185		- ppcxxx executable path: \$Env(HOME)/fpc/\$(UseFPCVersion)/lib/fpc/\$(UseFPCVersion)
189	186
190	187		#### Common bin folder (fpc executable + ppcxxx-XYZ symlinks) and separate lib folders using symlinks /usr/local/bin/ppcxxx-\$(UseFPCVersion) -\> /usr/local/lib/fpc/\$(UseFPCVersion)/ppcxxx
191	188
192	189		- fpc executable path: /usr/local/bin
193	190		- ppcxxx executable path: /usr/local/bin
194	191		- ppc executable has suffix: Yes
195	192
196	193		### Known issues
197	194
198	195		This is a work in progress and therefore not all options are functional. What needs to be completed is the prefix/suffix link between FPC Version Switcher and the IDE. Therefore options that pass paths or switches to the IDE should not be used for now.
199	196
200	197		### Wishlist
201	198
202	199		- To have a dropdown button next to the Run button so that switching FPC versions is done without even going into Tools/Options
203	200		- To have separate FPC versions for projects and the IDE
204	201
205	202		---
206	203		From the Free Pascal wiki, page "FPC Version Switcher", as it stood on 2015-02-27 after a change by Stephano, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).
207	204		Category: FPC
208	205		Category: IDE
209	206		Category: Lazarus
210	207		Category: Packages

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